Ohoho now that is rare.
That is a queen of Prenolepis nitens!
I should have thought of that as a possibility thinking back...^^
It is one of the rare ants that is active during all the winter. It is comperable to Myrmecocystus spp., it also has workers that get fed up to be really fat to save food for the winter.
I saw them in Croatia everywhere but forgot that you didn´t live in my cold parts of Europe.
They feed mostly of sugar like flowers and lice on plants and so on. The main time of activity is in the spring but in the fall, too, if I remember correctly they aren´t that active in the summer.
However the information that you should be interested in is; They found colonies claustral so you don´t need to feed her. Later they will probably feed on sugar (they didn´t eat honey when I tried to feed it to them in Croatia, only were interested in their lice). Cooling them down in winter is really important!
A really interesting ant. Never was able to catch any myself though I was in Croatia in spring once. :- (
EDIT: Here you might like this picture:
Hyperlinks sind nur für registrierte Nutzer sichtbar Phil took it when we were in Croatia in 2010. It shows how the worker will look like later. By the way they suck (?) on mealy bugs in that picture. <3